Device for finding ranges



April 8, 1924.-

A. Kc'jHLER DEVICE FOR FINDING RANGES Filed Aug. 15. 1921 Patent Apr. 8, i924.

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Application filed August 13, 1921. Serial No. 492,128.

To all whom it may concern:

Be it known that 1, AUGUST Konmm, a citizen of the German Empire, residing at Jena, Germany, have invented a new and 6 useful Device for Finding Ranges (for which I have filed an application in Germany May 25,1918, Patent 307,725), of which the following is a specification.

The present invention relates to a device 10 which is destined for finding ranges at night and which contains for this purpose two optical systems for producing two luminous fields on the object to be'measured. The relative position of the two luminous fields and their size substantially only depend on thedistance of the object to be measured, if the appertaining source of light beinvariable with regard to size and position. However, on this invariability must not be counted, either that the source of light, as

is the case with the arc lamp, is liable during the use to larger or smaller changes, or that new differences arise when exchanging an old glow lamp fora new one. The consequence thereof would be that the luminous fields will possibly not overla each other at the pro er place or not at a 1. Hence, it would not possible to draw a definite conclusion from the relative position of the so luminous fields upon the distance.

. This drawback may, however, be obviated by substituting for themore or less variable source of light the aperture of a diaphragm of a certain definite sha e and position. The images of these diap ragm a ertures represent the two. luminous fiel s. Any changes present in the osition and size of the source of light will then affect at the most the luminosity but in no case the position and size of the two luminous fields.

The device according to the present inventi'on contains a single source of light and two optical systems having a broken axis. Hence, the novel device forms substantially a single, compact body which may be easily supported crosswise to a craft.

D UNDER THE BROWSIONS 61 T ACT OF MARCH 3, 1921, 11 STAT. In, 1313.)

. The annexed drawing represents a constructional example of the invention, showing thesaid device, destined for an aircraft. 4

A tube a contains in its centre an incandescent lamp b. On either side of the-latter there are disposed two collective lenses 0 and 0?. Close behind the lens 0 lies a diaphragm (P, and close behind the lens 0 a diaphragm (1 At its ends the tube a is shutv off by means of the heads e and 6 The head 6 contains a collective lens 7 and a plane reflector 'g, the head 6 contains a collective lens 7 and a plane re fiector 9 The filament b of the incandescplnt lamp 6 is imaged, on the one hand, by t e lens 0 at the position of the lens 1 and, on the other hand,

osition of the lens f he diaphragm d 1s imaged on the ground by the lens 7 and the reflector g and likewise the diaphragm d by the lens f and the reflector 9 The reflectors g and g are so disposed that the place of the ages of the d1a hragm appear, lies outside the symmetrical plane of the air-craft, in case of the tube a being perpendicular to the said plane; the respective place of the ground can, therefore, be observed in a particularly convenient way.

I claim: 4

In a device for finding-ranges a source of light, two diaphragms lying at op osite sides of this source of light, two optica systems, each of which produces an image of one of the said diaphragms on the object to be measured and means .for deflecting the two ray pencil systems emerging from the said two 0 tical systems so as to be substantially para lel to each other.

AUGUST KOHLER.

Witnesses: Y

PAUL KRUGER, -RIOHARD HAHN.

-ound, in which the two imby the lens a at the 

